Question

在这里，我想合并可观察值的值。该代码有效，但是以这种方式进行嵌套订阅不是很好。我正在寻找更好的解决方案。预先感谢。

someObservable().subscribe(
      data => {                      // array of elements
        data.forEach(
          element => {
            anotherObservable(element.id)
              .subscribe(
                anotherData => doSomething(data, anotherData); // both data needed
              );
          }
        );
      }
    );

Answer 1

您可以使用 mergeMap

赞：

return this.someObservable().pipe(
  mergeMap(element=> this.anotherObservable(element.id).pipe(
    map(anotherData => {
      return {
        res1: element ,
        res2: anotherData 
      }
    })
  ))
)

Answer 2

您可以使用合并

点击here for Official Doc

例如：-

// RxJS v6+
import { mapTo } from 'rxjs/operators';
import { interval, merge } from 'rxjs';

//emit every 2.5 seconds
const first = interval(2500);
//emit every 2 seconds
const second = interval(2000);
//emit every 1.5 seconds
const third = interval(1500);
//emit every 1 second
const fourth = interval(1000);

//emit outputs from one observable
const example = merge(
  first.pipe(mapTo('FIRST!')),
  second.pipe(mapTo('SECOND!')),
  third.pipe(mapTo('THIRD')),
  fourth.pipe(mapTo('FOURTH'))
);
//output: "FOURTH", "THIRD", "SECOND!", "FOURTH", "FIRST!", "THIRD", "FOURTH"
const subscribe = example.subscribe(val => console.log(val));

结合可观察性与多个可观察性

2 个答案: